SMT differ
High density assembly, electronic products small volume, light weight, patch of components of the bulk and weight only traditional cartridge elements 10 or so, generally USES SMT after, electronic product size decreased 40% ~ 60%, and the weight 60% ~ 80%. SMT
High reliability and vibration-proof ability. Solder defects low.
Frequency characteristic well. Reduce the electromagnetic and rf interference.
Easy to realize the automation and improve production efficiency. Reducing cost up to 30% ~ 50%. Save material, energy, equipment, manpower, time, etc.
Why should use SMT
Electronic products used in pursuit of miniaturization, already cannot narrow plugin components perforation.
Electronic product function more complete, adoption of integrated circuit (IC) has no punched components, especially large-scale, high integration IC, have to use the surface patch components.
Product PiLiangHua, automated production, the manufacturer with low cost but high yield, produce high quality products to meet customer demand and strengthen market competitiveness
Electronic components development, integrated circuit (IC) development, semiconductor materials to multiple applications.
Electronic technology revolution is imperative, chasing after the international trend.
SMT basic process elements
Printing (or dispensing) - - - - > > mounted (cured) - - - - > > reflow soldering clean -- -- > > detection repair
printing
Its function is to solder paste or patch glue to its of the PCB soldering plate, and preparing for the components of welding. Equipment used for printing presses SMT processing workshop
(solder paste printer), located in the SMT production line of the front-end.
dispensing
For now is used mostly double-sided PCB patch, to prevent second down into the components for when solder paste again melting and peels, therefore, in input face plus deck glue machine, it is will glue drops to the PCB's fixed position, its main effect is components fixed to a PCB. Equipment used for dispensing machines, located at the forefront of SMT production line or testing equipment of behind. Sometimes due to the customer request output surface also need some glue, but now many small factories all need not dispensing machines, if input surface components bigger when employing worksite glue.
Pasted on
Its function is to surface assembly components installed to the PCB's fixed accurate position. Equipment used for placement machine, located in SMT production line of printing machines behind.
curing
Its function is to patch glue melting, thus making the surface assembly components and PCB firm bonding together. Equipment used for curing furnace, located in SMT production placement machine of behind.
Reflow soldering
Its effect is solder paste is melting, make surface assembly components and PCB firm bonding together. Equipment used for reflow oven, located in SMT production placement machine of behind.
cleaning
Its function is to assemble the good PCB above harmful to human body welding residues such as flux, etc to eliminate. Equipment used for cleaning machine, position can not fixed, can online, also don't online.
detection
Its function is to assembly good PCB assembly welding quality and quality detection. Equipment used have a magnifying glass, microscope, online tester (ICT), flying probe tester, automatic optical inspection (AOI), X RAY detection system, function - tester etc. According to the test needs, position can be furnished with production line appropriate place.
repair
Its function is to detect malfunction PCB board undertakes rework. Tools for iron and repair workstation, etc. Configuration in production line in any position.
SMT common knowledge introduction
1. Generally speaking, SMT workshop specified temperature for 25 + 3 ℃.
2 the printing, prepares the material and tools required for solder paste, steel, scraper, wipe paper, air-laid paper, cleaning agents, mixing sword.
3. Usually used for solder paste alloy ingredients, and Sn/Pb alloy alloy ratio for 63/37.
4 the solder paste in main ingredients into two most tin powder and flux.
5. Flux in the main function is to remove weld melting tin oxide, destroy the surface tension, prevent oxidation again.
6. The solder paste in tin powder particles and Flux (Flux) volume ratio of about 1:1, the weight ratio of about now.
7. The solder paste and use principle is advanced in first out.
8. The solder paste in kaifeng when using, shall undergo two important process back to temperature, stirring.
9. Steel common methods of producing for: etching, laser, electroforming.
10. SMT's full name is mounting Surface mount technology (or), Chinese meaning for the Surface adhesion (or mounted) technology.
11. The ESD is the full name of Electro - static fiberglass, Chinese meaning for electrostatic discharge.
12. Make SMT equipment applications, program, including five most, the five parts for PCB data, Mark data, Feeder data, Nozzle data, 'ts data.
13. Lead-free solder Sn/Ag/Cu 96.5/3.0/0.5 melting point for 217C.
14. Parts of the relative humidity controlled for drying oven < 10%.
15. Common passive components (PassiveDevices) are: resistor, capacitor, some sense (or diodes); etc. Active components (ActiveDevices) are: transistors, IC, etc.
16. Common SMT steel plate made of stainless steel.
17. Common SMT steel plate thickness.15 mm (or 0.12 mm).
18. Static charge produce kinds of friction, separation, induction, electrostatic conduction; etc. Static charge on the influence of the electronics industry for: ESD failure, electrostatic pollution; Static removing the three principles for electrostatic neutralization, grounding, shielding.
19. The imperial size long x width 0603 = 0.06 a * 0.03 a long x width size, metric 3216 = 320 mm * 1.6 mm.
20. Exclusion ERB - 05604 - J81 8 yards "4" expressed as four loops, resistance to 56 ohms. Capacitance ECA - 0105Y - M31 let value of C = 106PF = 1NF = 1X10 - due.
21. ECN Chinese all known as: engineering change notification, SWR Chinese all known as: special needs work, must by relevant departments counter-sign, document centers distributed reply.
22. The specific content of 5S to collating, rectify, cleaning, cleaning, literacy.
23. PCB vacuum packing is the purpose of dust-proof and moistureproof.
24. The quality policy for: total quality management, implement system, provide customer needs quality, Full participation, timely treatment, to achieve zero defect targets.
25. Quality three-no policy is: don't accept bad product, not manufacture defective product, not outflow non-conforming.
26. The QC seven gimmick in 4M1H respectively in the fishbone check reason means (English) : man, machines, materials, methods and environment.
27. The solder paste ingredients include: metal powder, soluble jinan, flux, resistance to vertical flow agent, surfactant, By weight points, metal powder of 85-92%, by volume points metal powder 50%, Including metal powder ingredient for tin and lead, proportion to 63/37, melting point for 183 ℃.
28. The solder paste must be used with from the refrigerator to temperature, the purpose is: let refrigeration solder paste temperature reply at normal temperature, eli printing. If you don't return temperature is in PCBA into Reflow easily after the adverse for tin beads.
29. Machine of document and supply mode are: prepare mode, priority exchange model, exchange model and speed connect mode.
30. SMT PCB localization way: vacuum positioning, mechanical hole positioning, bilateral clip positioning and plate edge localization.
31. Printing (symbol) 272 resistance, resistance is 2700 Ω, resistance is 4.8 M Ω resistance of symbols (printing) for 485.
32. BGA ontology of silk contains manufacturer, the manufacturer materials issue, specification and Datecode / (guernsey aubject) and other information.
33 the 208pinQFP pitch for 0.5 mm.
34 QC seven gimmick, the fishbone diagram emphasize find causality,
35. CPK refers to: at present practical situation of process capability,
36. Flux in constant temperature zone to begin volatile chemical cleaning action;
37. The ideal cooling zone curve and reflux area curve mirror relations;
38. Sn62Pb36Ag2 of solder paste main trial in ceramic plate;
39. Start with rosin primarily flux can be divided into four kinds: R, RA, RSA, RMA;
40. RSS curve for heating furnace-rough thermostatic - backflow - cooling curve,
41. We are currently using the PCB material for FR - 4,
42. No more than the PCB warping specifications diagonal 0.7%,
43. The STENCIL production laser cutting is ok again dhi method,
44. The present computer motherboard is used for 0.76 mm BGA ball diameter,
45. The ABS system for absolutely coordinate;
46. Ceramics chip capacitor ECA - 0105Y - K31 error more or less 10%,
47. Currently used computer PCB, its material for: glass fiber board;
48. SMT parts packaging its volume belt type dish for 13 inch in diameter, 7 inches,
49. SMT general steel myriapod than PCB PAD small 4um can prevent tin ball adverse phenomenon;
50. According to "PCBA inspection norms. When ErMianJiao > 90 degrees said solder paste and wave soldering body without adhesion,
51 after unpacking j IC card is greater than the humidity in the humidity 30% of cases said IC damp and moisture absorption,
52. Solder paste ingredients in tin powder and flux weight ratio and the volume ratio of right is 90% : 10%, 50% : 50%;
53. Early of the surface of sticky outfit technology originated in the mid 1960s the military and aerospace electronics field, 54. The current SMT most frequently used solder paste of Sn and Pb content of each 63Sn 37Pb; for:
55. Common bandwidth for 8mm tape materials plate for feeding spacing 4mm;
56. In the early 1970s, the industry have recently a SMD, for "sealed but no feet chip carrier", often in HCC Jane generation.
57. The symbol for the components of the resistance should be 272 2.7 K ohms,
58. 100NF component tolerance of the value and the same; 0.10 uf
59. 63Sn 37Pb the eutectic point for 183 ℃;
60. SMT usage's biggest electronics parts material is ceramics;
61. Back to welding stove temperature curve its curve 215C most suitable; the highest temperature
62. Tin stove when examination, tin stove temperature 245 ℃ more appropriate,
63. Plate opening roller type squares, triangles, round, astral form; this lei,
64. SMT section exclusion or without direction,
65. At present on market sale of solder paste, actual only 4 hours sticky time,
66. The SMT equipment use commonly 5KG/cm2 rated pressure for,
67. SMT parts maintenance tools are: soldering iron, hot air BaQu device, both absorb gun, tweezers,
68. The QC is divided into: IQC, IPQC and OQC FQC;.
69. High speed placement machine can be pasted on the resistor, capacitor, IC, transistors,
70. Electrostatic features: small current, influenced by humidity,
71. Positive, negative SMT PTH tin stove used what soldered turbulence double-wave welding;
72. SMT common inspection method: visual inspection, X-ray and machine visual inspection
73. Ferrochrome repair parts to the conduction convection heat transfer mode,
74. Currently BGA material its tin ball into Pb10; the main Sn90
75. The plate making method laser cutting and electroforming method, chemical etching,
76. The temperature according to eave welding stove temperature measurement him mad: using the applicable temperature,
77. Eave welding stove SMT semi-finished products in the export when its condition is fixed in welding parts on the PCB,
78. Modern quality management and development of the TQA - TQM; TQC -
79. ICT test is needle bed testing;
80. ICT test can measure electronic parts adopt static test,
81. Soldering characteristic is melting point than other metal low, physics performance meet the welding conditions, low temperature fluidity than other metal good;
82. Eave welding stove part replacement process conditions change to remeasure measure curve,
83. Siemens 80F/S belong to a electronic control transmission;
84. Solder paste thickness gauge is using Laser light measurement: the solder paste degrees, solder paste thickness and width of solder paste printed,
85. SMT parts feeding a vibrating type for distributor, discotic for distributor, roll belt for feeder,
86. SMT equipment use which institutions: CAM mechanism, side bar institutions, screw institutions, sliding institution,
87. Visual inspection section is required if cannot confirm in accordance with any assignment BOM, manufacturer confirmed, sample plate;
88. If parts for 12w8P packing method, the counter Pinth size must be adjusted each into 8mm;
89. Eave welder sort: hot air type eave welding stove, nitrogen eave welding stove, laser eave welding stove, infrared eave welding stove.
90. SMT parts can be used for sample test method: streamline type production, fingerprints machine mounted, handprint hand mounted,
91. Common MARK shape has: round, "10" glyph, square, triangle, the diamond, million glyph,
92. Reflow Profile Settings for SMT section undeserved, may cause parts micro cracked is preheating zone, cooling zone;
93. SMT period ends heated parts easy create: empty uneven welding, and deviation of, tombstones,
94. High speed machine and domestic machine should as far as possible equilibrium; a pa
95. The quality is the intendment of do it right the first time,
96. Placement machine should first post small parts, after stick big parts;
97. BIOS is a basic Input/Output System, the full English Base Input/Output for: views,
98. SMT parts according to parts feet can be divided into two kinds of LEADLESS and organization;
99. Common automatic placement machine there are three basic types, succeeded type placed type, type and large weave-machines.continuative placed transfer type placed machine,
100. The SMT process without LOADER can also production.
101. SMT process was delivering plate system - solder paste printer - high speed machine - domestic machine - separated flow welding - unloader,
102. The temperature sensitive parts kaifeng, humidity card circle show color to blue, parts can be used;
103. The specification of 20mm not strip width,
104. Cheng for printing adverse short-circuited reasons: a. solder paste metallic content enough, causing collapse b. steel openings caused by excessive, the tin quantity overmuch cristiano steel quality was not good, bad, change under the tin on the back d.S laser cutting template tencil solder paste, lower residual have squeegee pressure, using appropriate VACCUM and SOLVENT
105. General back welding stove Profile of the main engineering districts purpose: a. preheating zone; Engineering objective: the solder paste zhongrong agent volatile. B. mean temperature area, Engineering objective: flux activation, remove oxides, Evaporation excess water. C. back welding area, Engineering objective: solder melting. D. cooling zone; Engineering objective: alloy solder formation, feet and pad connect parts for an organic whole;
106. SMT process, tin bead the main causes of the: PCB design, improper PAD plate opening of poor design, buy thing depth or buy thing too much stress, Profile curve rose slope too large, solder paste viscosity collapsed, too low.
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